This relates to wireless electronic devices and more particularly, to ways of operating wireless electronic devices in a radio-frequency communications network.
Electronic devices such as handheld electronic devices, portable electronic devices, and computers are often provided with wireless communications capabilities. Electronic devices with wireless communications capabilities include antennas that serve to transmit and receive radio-frequency signals.
In many applications, it may be desirable to determine the relative location of different components in a network. The different components are sometimes referred to as “nodes” in the network. Conventional relative positioning techniques typically involve estimating times-of-flight (TOFs) between pairs of nodes in the network. In wireless networks where locking nodes to a common time base is not practicable, estimation of TOF requires round-trip time (RTT) estimation between each pair of nodes in the network.
During typical RTT estimation procedures, a first node transmits a packet to a second node. After a deterministic internal turn-around delay, the second node transmits a return packet back to the first node. The first node then processes the return packet to estimate a corresponding round-trip time. The first node may then repeat this process with a third node in the network. This process may be iterated for each respective pair of nodes in the network. When performing this type of RTT estimation, only two nodes are active at any given point in time. As a result, performing relative positioning of multiples nodes in a wireless network can be undesirably time-consuming, particularly when the network includes a large number of nodes.
It may therefore be desirable to provide improved methods for determining the relative positions of different nodes in a wireless network.